Janae Barbury
Class: Thurs 10 – 12:15 AM
Article Summary
Serologic Survey for Selected Disease Agents in Wolves (Canis Lupus) From Alaska and the
Yukon Territory. Randall L Zarnke, Jay M. Hoef, and Robert A. Delong. 1984 - 2000
Wolves are a Keystone Species both biologically and politically in Alaska and
the Yukon Territory due to their effects on the prey population. Without the wolves, prey
populations infest the land and expand too quickly, faster than the land can replenish
itself. Population dynamics of Wolves are influenced in many ways. Two main factors
are: harvest by humans and availability of their prey. Disease serves as a source of
mortality in wolves as well. Opportunity for interaction with other candid species was
found to serve as possible disease transmission to wolves. 6 six disease agents were
studied in survey: Infectious canine hepatitis virus, Canine parvovirus, canine distemper
virus, Francisella tularensis and Leptospira interogans.
The ambition of the study was to try to determine the effect of age, sex, location
and time of collection of serum antibody prevalence in carrier wolves as well as disease
transmission to the wolf populations in Alaska and the Yukon Territory from several
areas. Wolves were captured by employees for testing. Pups and adults were
distinguished by their physical characteristics. Age and population estimates were only
available for a narrow time period perhaps because of disease. Blood was collected and
serum removed. Sera were tested for the presence of antibodies fighting off any of the six
diseases being tested(Infectious canine hepatitis virus, Canine parvovirus, canine
distemper virus, Francisella tularensis and Leptospira interogans.)
. Samples were sent to different laboratories to make testing quality unchanging
for all samples. At the Wyoming State Veterinary Laboratory both serovars of canine
distemper were tested by means of serum neutralization; serovars of L.interrogans were
tested by means of microscopic agglutination testing; National Veterinary Services
Laboratory tested canine parvovirus, infectious canine hepatitis virus by my means of
serum neutralization testing. Alaska Department of Fish and Game tested F. tularensis by
means of rapid plate agglutination testing.
Threshold titer
Disease
16
Canine Distemper virus
100
L. interrogans
36
Canine parvovirus and
Infectious canine hepatitis virus
20
F. tularensis
Specimens with titers that met or surmount thresholds were acknowledged as
auspicious of previous natural exposure referred to as “positive” in the study and all
others were considered “negative”. Antibody titers are short lived because the strength of
the solution was found to be low. Success in a pack was used to help see if there was an
implication dependence of antibody prevalence on age, sex, year and location of when
samples were taken. Age, sex and geographic location was treated as an absolute
variable, age having two classes: pups and adults. Pups were only samples in some
geographic units so only data for adult animals were looked to for answers. Year sample
was taken was treated as a continuous variable. Antibody prevalence variations were
great with different sites and difference in age.
Prevalence increased during the study and was no sex-specific differences in
prevalence for any of the diseases in the study. Antibody prevalence to ICH increased
maybe due to the ten year storing period probably because some of the antibody portion
denatured is the only readily apparent explanation. Transmission ways were by infected
prey, urine and feces from infected animals the wolves came into contact with. No
apparent geographic or chronologic pattern besides being higher in remote areas and
signs similar to those in domestic dogs. Leptospirosis causes chronic kidney infections,
hepatitis and abortion in a broad spectrum. Antibody Prevalence for L. interrogans being
low in study these results concur with a previous study with wolves in Alaska. Tularemia
is an acute, febrile plaguelike disease caused by the bacterium F. tularensis. 2001 Snow
shoe hairs, a prey of the wolves, showed clinical signs of tuleremia and were found to be
the primary hosts. Prevalence of clinical tularemis in hares peaked with their population
density so wolves who ate the rabbits during this peak would show serologic evidence of
exposure to F. tularensis. Furthermore antibody titers being short lived wolves being
exposed to leptospires is simply rare and not a significant source of morbidity or
mortality for wolves.